Each day a different image or photograph is featured, with an
accompanying caption, which deals with various topics in Earth Science.

Altocumulus Clouds and Lunar Corona

The photo above of a lunar corona and nighttime clouds was taken on January 12, 2006 from Kenwood, California. On this winter's night the partially concealed Moon was just shy of being full and is framed here by altocumulus undulatus clouds. Characteristic droplet sizes and concentrations of mid level clouds quite often produce coronas when positioned near the Sun or Moon. Coronas are created by the process of diffraction -- light waves are deflected by water droplets of near uniform size. After light strikes the droplets, interference rings are generated by the outgoing light waves, forming regions of enhanced brilliance,and darkness.